Kay,
Not sure if we've corresponded before on this subject.
I think your 'Roger' may be my 2nd Gt Grand Uncle (brother to Thomas Prosser (1805 - 1884), therefore son of David Prosser and Magolan (Magdalen or Martha) Wathen (married 8 Dec 1804, Aberedew).
I've got Roger being born about 1819, and marrying Mary Lloyd 17 April 1854 at Llandilo Graban. They had 3 sons, James (abt 1853), David 1856 and William 1860.
Regards
David